Cable anchor



F. J. M HUGH CABLE ANCHOR Filed Sept. 5, 1955 2 Sheets-Sheet l Ema @"T'ATTORNEY @ci'. 4, 1938. I F. .J. MCHUGH CABLE ANCHOR Filed Sept. 5, 19352 Sheets-Sheet 2 Patented Oct. 4, 1938 PATENT OFFICE CABLE Frederick J.McHugh,

Application September In Canada 11 Claims.

This invention relates to cable anchors and particularly to improvedmeans for anchoring individual strands of the large multiple strandcables used in the construction of suspension bridges.

According to one feature of this invention the cable strands areanchored at points equi-distant from the splay point of the cable byspheroidal disposition of the points of anchorage about a common centercoinciding with said splay point. This arrangement lends itself .to theuse of strands of equal length, thereby simplifying the strandmanufacturing, pre-stressing and erection operations.

Another feature ofthe invention consists in the provision of a generallyimproved form of anchorage for the cable strands whereby the loads aretransferred direct to masonry concentric'with the pull on said strands.

A further feature of the invention consists in fastening the cablestrands to one or more anchor plates by suitable fittings which may beconveniently adjusted to selectively tension the strands in the eventthat the main centers of crossing or lengths of the strands areincorrect.

A still further feature consists in the provision of an improved form ofmultiple-strand cable anchorage which lends itself to economicfabrication and erection and'which may be conveniently incorporated in'the construction of a bridge pier or other masonry to which the loads onthe strands are to be transferred.

Proceeding now to a more detailed description of the invention referencewill be had to the accompanying drawings, which Fig. 1 is a view in sideelevation of one form of cable anchorage provided in accordance withthis invention.

Fig. 2 is a plan view of a one-piece anchor plate to which the cablestrands are fastened so that the points of anchorage are spheroidallydisposed about a common center coinciding with the splay point of the"cable.

Fig. 3 is a detail view showing the manner in which the cable strandsare fastened to the anchor plate as well as the manner in which theanchor plate is fastened to the main frame and other elements of theanchorage.

Fig. 4 is a top plan view of the main frame appearing in Figs. 1 and 2.

Fig. 5 is a view in elevation of the rear portion of the main frame.

Fig. 6 is a view in elevation of the front tion of the mam frame. I

ANCHOR Dorval, Quebec, Canada 5, 1935, Serial No. 39,326 July 6, 1935Fig. 7 is a view similar to Fig. 1 but showing a modified form ofanchorage.

Fig. 8 is a sectional view along the line 8-8 of Fig. '7.

Fig. 9 is a fragmentary plan view taken as indicated by line 9-9 of Fig.8.

Fig. 10 is a sectional view taken along the line |0--l0 of Fig. 9..

Referring more particularly to Figs. 1 to 6 inclusive, 5 designates aone-piece anchor plate to which the strands 6 of cable 1 are fastened byadjustable fittings generally indicated at 8. Each fitting 8 includes athreaded bolt 9 passing through an opening ID in plate 5, one end ofsaid bolt being fitted with a nut bearing against a spherically curvedsurface l2 of the plate, the other end of said bolt being pivotallysecured in the eye portion l3 of socket member I fixed to one of thecable strands 6. When plate 5 is anchored in place as hereinafterdescribed the strands 6 may be selectively tensioned by appropriatemanipulation of the nuts The plate openings l0 through which the bolts 9pass are normal to the spherically curved surface l2 and, as shown inFig. 2, are arranged in groups of fourwith the component openings ofeach group symmetrically arranged about one of a series of furtheropenings |5 formed in said plate. The openings l5 are provided toreceive therethrough a series of anchor bolts l6 which extend indirection radially of the splay point of the cable. The anchor bolts areassembled with the plate as shown in Fig. 1 where it will be noted thatthese bolts pass through the openings l5 into threaded engagement withsuitable internally threaded collars welded to the flat face of plate 5in line with openings I5. In addition to passing through the plate 5 theanchor bolts l6 pass through a suitable arrangement of openings l8 and.I9 provided in front and rear spacer plates 20 and 2| which areconnected to each other by suitable frame members 22 to form the framestructure generally indicated at 23. The frame structure 23 is designedand installed so that the rear plate 2| is supported in a verticalposition on masonry foundation 24 while the front plate is supported ina vertically inclined position on a portion 24a of the foundation whichis at a higher elevation than that on'which the rear plate 2| issupported. In this connection it will be noted that the two plates 20and 2| are connected by the framing members 22 so that the plate 20is'positioned withits upper and lower edges at a higher level than thecorresponding edges of the plate 2| and with its lower edge spaced agreater distance from plate 2| than its upper edge. The openings l8 andIQ of plates 20 and 2| are arranged in circles of sufiicient diameterpredetermined to take care of the divergence of the rods l6 which passthrough openings in the anchor plate 5 and extend in directions radiallyof the splay point of the cable. The anchor plate .5 is preferablymaintained in spaced relation to the front plate of frame 23 by a seriesof tubular members 25 surrounding portions of the rods l6, one end ofeach tubular member being welded to the plate 20 and the other end tothe spherically curved surface l2 of plate 5. not shown in the presentdrawings it will be understood that the anchor rods l6 and the frame 22,after being installed as shown in 'Fig. 1, are embedded in a mass ofconcrete forming part of a pier or other masonry structure to which theloads on the cable strands 6 are to be transferred.

Figs. 7 to 10 inclusive illustrate a modification in which single plate5 is replaced by a plurality of plate sections 26 designed to serve thesame purpose. These plate sections are clamped in place between theopposing grooved portions 28 of a series of anchor plates 29 heldtogether by suitable clamping bolts 30. The surfaces of plate sections26 which are engaged by the nuts II are spherically curved, as indicatedat 26a, about a common center coinciding with the splay point of thecable with the result that the anchorage points of the cable strandsarespheroidally disposed about the splay point of the cable in the samemanner as described in connection with Figs. 1 to 6 inclusive.

A feature common to both of the installations described herein is thatthe cable strands are anchored at points spheroidally disposed about thesplay point of the cable so as to be equi-distant therefrom. This isprovided for, in Figs. 1 to 6 inclusive, by the spherically curvedsurface I 2 of the one-piece anchor plate 5 to which the cable strandsare anchored by the nuts II. The same result is obtained in Figs. 7 to10 inclusive by providing the anchor-plate sections with the sphericallycurved surfaces 26a for engagement with the strand anchoring nuts II.

To avoid bending of the strands or strand connections it is important,in connection with the construction illustrated in Figs. 1 to 6inclusive, that the openings l0 and I5 through which the bolts 9 and I5pass be normal to the curved surface [2 of plate 5. The grouping of thebolt receiving openings l0 so that the component openings of each groupare symmetrically disposed about one of the bolt receiving openings I5is also important since it facilitates uniform transmission of loads tothe masonry along lines parallel with the direction of pull on thestrands.

Having thus described my invention, what I claim is:

1. Means for anchoring the strands of a multiple strand cable comprisinga single anchor plate to which all of the strands are adjustablyconnected and anchor rods through which the strand loads imposed ontheanchor plate are transferred direct to. masonry concentric with thepull on said strands.

2. Means for anchoring the individual strands of a multiple strand cablecomprising a single anchor plate having one side spherically curvedabout a center coinciding with the splay point of the cable and meansfor adjustably anchoring While the cable strands to the curved side ofthe plate.

3. Means for anchoring the individual strands of a multiple strand cablecomprising an anchor plate having one side spherically curved about acenter coinciding with the splay point of the cable and means foradjustably anchoring each strand to such curved side of the anchor plateso that the points of anchorage thus established are spheroidallydisposed about the splay point of the cable and are equi-distanttherefrom, said last mentioned means being adjustable to permitselective tensioning of the strands.

4. Means for anchoring the strands of a multiple strand cable comprisinga single anchor plate to which all of the strands are adjustablyconnected by fittings permitting selective tensionin of the strands, anda series of anchor bolts connected to the anchor plate for transmittingthe pull of the strands from the anchor plate direct to masonry in whichthe anchor rods are embedded.

5. Means for anchoring the strands of a multiple strand cable as setforth in claim 4 in which said fittings are connected to the anchorplate in groups so that the component fittings of each group aresymmetrically arranged about one of the anchor rods.

6. Means for anchoring the individual strands of a multiple strand cablecomprising a single anchor plate, a'series of bolts passing throughspaced openings formed in said plate, one end of each bolt beingattached to a socket member fixed to one of the cable strands and theopposite end being fitted with a nut bearing against the side of theplate remote from the said socket member, the last mentioned side of theplate being spherically curved about a center coinciding with the splaypoint of the cable.

7. Means for anchoring the strands of a multiple strand cable as setforth in claim 6 in which the openings through which said bolts pass arenormal to the spherically curved surface of the plate. V

8. Means for anchoring the individual strands of a'multiple strand cablecomprising a single anchor plate having one side spherically curvedabout a center coinciding with the splay point of the cable, a series ofbolts passing through spaced openings formed in said plate, each bolthaving one end fitted with'a nut bearing against the spherically curvedside of the plate and the other end attached to a socket member fixed toone of the cable strands at the opposite side of the plate, a pluralityof anchor bolts passing through further openings formed in said plateand secured thereto and a frame structure provided with bolt receivingopenings through which the anchor bolts extend, said frame structurebeing located at the curved side of said plate, said frame structure andanchor bolts being adapted to be embedded in masonry to resist the pullof the cable strands on said plate.

9. Means for anchoring individual strands of a multiple strand cablecomprising a plurality of anchor rods, a frame in which said rods areheld in predetermined spaced angular relation so that said rods extendin directions radially of the splay point of the cable, said frame androds being adapted to be embedded in a concrete or masonry structure towhich the loads on the cable strands are to-be transferred, and meanssecuring the cable strands to the cable endsof said rods so that thestrands are anchored at points spheroidally disposed about the splaypoint of the cable.

10. Means for anchoring individual strands of a multiple strand cablecomprising a plurality of anchor rods, a spacing frame in which the rodsare held in predetermined angular spaced relation so that the rodsextend in directions radially of the splay point of the cable, saidframe and rods being adapted to be embedded in a concrete or masonrystructure to which the loads on the cable strands are to be transferred,and adjustable connections through which the cable strands are connectedto the cable ends of the anchor rods so that the strands are anchored atpoints spheroidally disposed about the splay point of the cable.

11. Means for anchoring individual strands of a multiple strand cablecomprising a plurality of anchor rods embedded in a concrete or masonrystructure to which the loads on the cable strands are to be transferred,said rods being arranged in predetermined spaced angular relation toextend in directions radially of the splay point of the cable and meansconnecting the cable strands to the cable ends of said rods to anchorthe strands at points spheroidally disposed about the splay point of thecable, the arrangement being such that bending of the cables at theirpoints of anchorage is substantially avoided.

FREDERICK J. Mcl-IUGH.

